3-D shape measurement endoscope using a single-lens system

Purpose A three-dimensional (3-D) shape measurement endoscopic technique is proposed to provide depth information, which is lacking in current endoscopes, in addition to the conventional surface texture information. The integration of surface texture and 3-D shapes offers effective analytical data and can be used to detect unusual tissues. We constructed a prototype endoscope to validate our method. Methods A 3-D measurement endoscope using shape from focus is proposed in this paper. It employs a focusing part to measure both texture and 3-D shapes of objects. Image focusing is achieved with a single-lens system. Results A prototype was made in consideration of proper endoscope sizes. We validated the method by experimenting on artificial objects and a biological object with the prototype. First, the accuracy was evaluated using artificial objects. The RMS errors were 0.87 mm for a plate and 0.64 mm for a cylinder. Next, inner wall of pig stomach was measured in vitro to evaluate the feasibility of the proposed method. Conclusion The proposed method was efficient for 3-D measurement with endoscopes in the experiments and is suitable for downsizing because it is a single-lens system.     

Functional anatomy of the shoulder complex

The shoulder complex, together with other joint and muscle mechanisms of the upper limb, primarily is concerned with the ability to place and control the position of the hand in the visual work space in front of the body. The shoulder mechanism provides the upper limb with a range of motion exceeding that of any other joint mechanism. The placement of the hand is determined by four components of the shoulder complex: the glenohumeral, acromioclavicular, and sternoclavicular joints and the scapulothoracic gliding mechanism. The clavicular joints permit the scapula to move against the chest wall during movements of the arm, allowing the glenoid fossa to follow the head of the humerus, and thus contribute significantly to total arm movement. The functional interrelationships between the glenohumeral, scapulothoracic, and clavicular joint mechanisms are critical in providing a full, functional ROM. Any pathological condition of any one of these mechanisms will disturb upper limb function. The ligamentous and periarticular structures of the shoulder complex combine in maintaining the joint relationships, withstanding the forces applied to the joint surfaces, and stabilizing the dependent limb.     

Two-dimensional ultrasound measurement of thyroid gland volume: a new equation with higher correlation with 3-D ultrasound measurement

This study aimed to develop a new two-dimensional (2-D) ultrasound thyroid volume estimation equation using three-dimensional (3-D) ultrasound as the standard of reference, and to compare the thyroid volume estimation accuracy of the new equation with three previously reported equations. 2-D and 3-D ultrasound examinations of the thyroid gland were performed in 150 subjects with normal serum thyrotropin (TSH, thyroid-stimulating hormone) and free thyroxine (fT4) levels (63 men and 87 women, age range: 17 to 71 y). In each subject, the volume of both thyroid lobes was measured by 3-D ultrasound. On 2-D ultrasound, the craniocaudal (CC), lateromedial (LM) and anteroposterior (AP) dimensions of the thyroid lobes were measured. The equation was derived by correlating the volume of the thyroid lobes measured with 3-D ultrasound and the product of the three dimensions measured with 2-D ultrasound using linear regression analysis, in 75 subjects without thyroid nodule. The accuracy of thyroid volume estimation of the new equation and the three previously reported equations was evaluated and compared in another 75 subjects (without thyroid nodule, n = 30; with thyroid nodule, n = 45). It is suggested that volume of thyroid lobe may be estimated as: volume of thyroid lobe = 0.38.(CC.LM.AP) + 1.76. Result showed that the new equation (16.9% to 36.1%) had a significantly smaller thyroid volume estimation error than the previously reported equations (20.8% to 54.9%) (p < 0.05). There was a significantly larger thyroid volume estimation error when thyroid glands with nodules were examined (p < 0.05). With the use of the appropriate thyroid volume equation, 2-D ultrasound can be a useful alternative in thyroid volume measurement when 3-D ultrasound is not available.     

3-D measurement of body tissues based on ultrasound images with 3-D spatial information

In this study, we developed a new method to perform 3-D measurements between the recorded B-scans using the corresponding spatial location and orientation of each B-scan, without the need to create a 3-D volume. A portable ultrasound (US) scanner and an electromagnetic spatial locator attached to the US probe were used. During data collection, the US probe was moved over the region-of-interest. A small number of B-scans containing interesting anatomical information were captured from different body parts and displayed in a 3-D space with their corresponding locations recorded by the spatial locator. In the B-scan planes, the distance between any two points, as well as the angle between any two lines, could be calculated. In validation experiments, three distances and three angles of a custom-designed phantom were measured using this method. In comparison with the results measured by a micrometer, the mean error of distance measurement was −0.8 ± 1.7 mm (−2.3 ± 3.6%) and that of angle measurement was −0.3 ± 2.9° (−0.1 ± 4.1%). The lengths of the first metatarsals and the angles between the first metatarsals and the middle part of the tibias of three subjects were measured in vivo using magnetic resonance imaging (MRI) and the US method by two operators before and after MRI scanning. The overall percentage differences of the length and angle measurements were 0.8 ± 2.2% and 2.5 ± 3.6%, respectively. The results showed that this US method had good repeatability and reproducibility (interclass correlation coefficient values > 0.75). We expect that this new method could potentially provide a quick and effective approach for the 3-D measurement of soft tissues and bones in the musculoskeletal system.     

The effect of shoulder movements on thoracic spine 3D motion

OBJECTIVE: To investigate whether there is any repeatable coupling pattern of upper thoracic movements, during right arm elevation in sagittal and scapular plane. METHODS: Upper thoracic movement patterns (T2-T7) were examined during right arm elevation, in the sagittal and scapular plane using an electromagnetic device. The participants were 25 asymptomatic woman aged between 45 and 64 years. RESULTS: The majority of the participants performed an ipsilateral coupling pattern between lateral flexion and rotation which was repeatable and comparable for both arm elevation planes. Ipsilateral coupling of right lateral flexion and rotation in association with extension occurred in 23 subjects during arm elevation in sagittal plane, and in 19 subjects during arm elevation in scapular plane. CONCLUSIONS: Analysis revealed that the participants demonstrated a repeatable upper thoracic movement pattern within and between subjects, during arm elevation in sagittal and scapular planes. RELEVANCE: The biomechanical relationship between the arm and the thoracic spine is important to clinical practice because of the contribution of spinal to shoulder movements and vice versa, in the recognition, prevention and restoration of musculoskeletal function.     

Isometric shoulder muscle activation patterns for 3-D planar forces: a methodology for musculo-skeletal model validation

OBJECTIVE: To present an isometric method for validation of a shoulder model simulation by means of experimentally obtained electromyography and addressing all muscles active around the shoulder joints. BACKGROUND: Analysis of muscle force distribution in the shoulder by means of electromyography during motion tasks is hampered by artificial and non-linear amplitude modulation and is often limited to downward directed external forces. This application of EMG is therefore inadequate and insufficient for the validation of shoulder model simulations. We suggest an isometric method including multi-directional forces to overcome these problems. METHODS: A force with constant magnitude is actively rotated stepwise in 20 directions perpendicular around the arm while kept in one position. The isometric muscle activation (EMG) is a function of the clockwise-rotated force angle, characterized by baseline activation, and a section of increased muscle activation characterized by baseline interception and direction and magnitude of maximum muscle activation. Comparison of the parameterized muscle activation with predicted muscle forces from model simulation illustrates the applicability for musculo-skeletal model validation. RESULTS: All recorded shoulder muscles were active over a section of force angles of at least 180 degrees. Some muscles demonstrated two activation sections. The estimated model sensitivity for the baseline interception was SD=5 degrees -10 degrees. The Principal Action was the most reliable parameter (SD=4 degrees ). A correlation of 0.778 was observed between model simulations and EMG recordings. CONCLUSIONS: The methodology addresses all shoulder muscles over a substantial section of planar force directions. This enables the comparison of experimentally determined direction of activation on- and offset and direction of maximum activation with equivalent muscle forces, predicted from model simulation.     

Within-day reliability of shoulder range of motion measurement with a smartphone

Measuring range of motion (ROM) is the first step of a physical examination and functional evaluation of the shoulder joint. Digital inclinometers are available on the market; however, they are expensive, and hence will not come into wide use. In this study, we present a new method for the shoulder ROM measurement using the inclinometer application on a smartphone. We hypothesized that the method would demonstrate acceptable reliability and reproducibility. Three observers performed goniometric and smartphone inclinometric measurements of various shoulder movements, including both active and passive ROM for forward flexion, abduction, external rotation while the arms are at the sides, external rotation at 90° abduction, and internal rotation at 90° abduction. Measurements were performed in the affected shoulders of 41 patients. All measurements were taken twice to assess the intra-observer reliability. Inter- and intra-observer reliabilities were evaluated using the intraclass correlation coefficient (ICC). Reliability between two measurements was also assessed in terms of the ICC. Both the goniometric and inclinometric measurements showed satisfactory inter-observer reliability except for internal rotation at 90° abduction for which the ICC value was <0.7 (range, 0.63-0.68). Intra-observer reliability was excellent with an ICC value>0.9, except for some movements. Within-day inclinometric measurements with a smartphone showed acceptable reliability compared to the classical goniometric measurements of movements and the correlation between the two measurements was fairly high. Considering convenience and cost-effectiveness, this new method could be widely used for measuring the shoulder ROM, although the between-day reliability needs to be established first.     

Chronic neck pain and muscle activation characteristics of the shoulder complex

IntroductionNeck pain is a very common musculoskeletal complaint in industrialized countries. Theoretically, chronic neck pain is thought to possibly change biomechanics and muscle activation patterns of the shoulder complex, causing its pain and dysfunction in the long term.PurposeThe present cross-sectional study was conducted to compare shoulder complex muscle activation characteristics in patients with chronic non-specific neck pain, compared to healthy participants.MethodTwenty patients with chronic neck pain and twenty healthy participants were recruited for the present study. Surface Electromyographic (sEMG) activity was recorded from four selected muscles (anterior and middle deltoid, upper and lower trapezius) during shoulder elevation with a predetermined load (25–30% of an individual's maximum voluntary exertion).ResultResults revealed only two significant increased onset delays in the anterior and middle deltoid,and a peak delay in the upper trapezius in chronic neck pain patients. Furthermore, increased onset delay for other muscles and decreased peak normalized amplitude (MVE%) for all muscles were found in chronic neck pain patients; however, these findings were not statistically significant.ConclusionThere were relationships between chronic non-specific neck pain and the shoulder muscle activation characteristic; hence, the alteration may be considered a predisposing factor for the shoulder dysfunction in future studies.     

Temperature measurement and control system for transtibial prostheses: Functional evaluation

The accumulation of heat inside the prosthetic socket increases skin temperature and fosters perspiration, which consequently leads to high tissue stress, friction blister, discomfort, unpleasant odor, and decreased prosthesis suspension and use. In the present study, the prototype of a temperature measurement and control (TM&C) system was designed, fabricated, and functionally evaluated in a phantom model of the transtibial prosthetic socket. The TM&C system was comprised of 12 thermistors divided equally into two groups that arranged internal and external to a prosthetic silicone liner. Its control system was programmed to select the required heating or cooling function of a thermal pump to provide thermal equilibrium based on the amount of temperature difference from a defined set temperature, or the amount of difference between the mean temperature recorded by inside and outside thermistors. A thin layer of aluminum was used for thermal conduction between the thermal pump and different sites around the silicone liner. The results showed functionality of the TM&C system for thermoregulation inside the prosthetic socket. However, enhancing the structure of this TM&C system, increasing its thermal power, and decreasing its weight and cost are main priorities before further development.     

结节性硬化症伴多系统损害的影像学表现

目的：分析结节性硬化多器官多系统损害的影像学表现,提高对结节性硬化全面认识。方法 ：回顾性分析10例临床确诊的结节性硬化伴多器官损害的临床及影像学资料,了解颅外器官损害及病理类型。结果：10例均有特征性颅内结节,1例伴室管膜下巨细胞星形细胞瘤;8例累及肾脏,均为双侧肾脏多发血管平滑肌脂肪瘤,其中1例伴双肾多发小囊肿,1例伴瘤内动脉瘤,1例伴肝脏多发血管平滑肌脂肪瘤,2例伴肺淋巴管平滑肌瘤病,2例伴心室腔内横纹肌瘤,其中1例伴先天性肛门畸形;1例同时累及肾脏、骨骼及大血管;1例伴胰腺神经内分泌肿瘤;1例膝关节皮下纤维瘤伴同侧关节腔积液。结论：结节性硬化除颅脑特征性结节外,身体其他系统器官也可出现受损害表现,了解其影像学表现,有助于提高结节性硬化的诊断。     

Air mattress sensor system with balancing tube for unconstrained measurement of respiration and heart beat movements

The cardio-respiratory signal is a fundamental vital sign used for assessment of a patient's status. Additionally, the cardio-respiratory signal provides a great deal of information to healthcare providers wishing to monitor healthy individuals. The air mattress sensor system allows the measurement of the respiration and heart beat movements without the use of a harness or sensor on the subject's body, which eliminates the difficulties these pose for long term measurements. In order to increase the sensitivity, a differential measurement technique between two air cells was used. The concept of a balancing tube between two air cells is suggested in order to increase the robustness against postural changes during the measurements. With this balancing tube, the meaningful frequency range could be selected using a pneumatic method. A mathematical model was constructed and validation experiments were performed for step and sinusoidal input signals. This technique was applied to measurements of respiration and heart beat movements in the supine posture on the bed, which showed potential for applications in sleep analysis, unconstrained healthcare monitoring and neonate monitoring.     

Freehand ultrasound elastography with a 3-D probe

This paper presents the first near-real-time freehand ultrasound elastography system using a (3-D) mechanical probe. Acquisition is complete within two sec, and only an additional 20 sec are required for generation of a full 3-D strain volume. The strain is axial, with estimates of lateral and elevational tissue movement used to increase the accuracy of the axial strain measurement. This is the first time all system components have been extended to 3-D, i.e., 3-D windows are used to track displacement, which is tracked in all directions, and 3-D kernels are used for least-squares gradient estimates. Normalization of the freehand 3-D strain data is also applied across the whole volume. The system is tested using a novel research 3-D radiofrequency (RF) system with real-time control over the stepper motor driving the ultrasound probe, and real-time streaming of RF ultrasound data. The paper proves the concept, rather than making significant comments on the achievable accuracy in 3-D, although we demonstrate that the high performance of the 2-D techniques that we extend appears to carry through to in-vitro and in-vivo 3-D data. The result is a fast and high-resolution 3-D image of normalized axial strain. (E-mail: gmt11@eng.cam.ac.uk).     

The Actifetus system: a multidoppler sensor system for monitoring fetal movements

Fetal heart rate (FHR) monitoring is a crucial part of monitoring at-risk pregnancies and labor. Its aim is to detect any abnormalities that might indicate acute fetal distress and a need for rapid treatment to avoid death or serious sequelae, including cerebral handicap. The use of fetal biophysical profiles in high-risk pregnancies (gravidic hypertension, in utero infection, etc.) helps to distinguish healthy fetuses from those with chronic conditions. Fetal biophysical profile scores have been developed that integrate five biophysical parameters, one of which is derived from the FHR. The major parameters detected are the rate of fetal movements, fetal tone, fetal breathing movement and amniotic fluid volume. All of those parameters except FHR are obtained by prolonged echographic observation and cannot be used routinely. We developed in this study a new multigate multitransducer pulsed Doppler system for survey of fetal behavior. Fast Fourier transform and autocorrelation function have been used for processing and analyzing ultrasonic Doppler signals generated by fetal movements. Several parameters are analyzed in each of the 12 x 5 = 60 Doppler gates: amplitude of signals reflected by moving fetal structures, velocity, direction and amplitude of displacement of fetal structure (heart, chest, limbs). From these parameters it is possible to calculate FHR and characterize fetal activity. Preliminary in vivo results obtained in 15 pregnant women (30 to 36 wk) are very encouraging but they have yet to be confirmed in future studies. These results also demonstrate the advantages of transducers designed for improved fetal movement detection. The algorithms needs to be precise enough to allow the Actifetus system to function in real time. We now have at our disposal some algorithms that succeed in quantifying FHR and fetal movements with a signal from a given sensor at a given depth. This study confirms the feasibility of monitoring fetal movements by the Actifetus system and demonstrates the importance of the characterization of fetal rhythms (and fetal behavior). The Actifetus system will serve as a new mean for studying fetal response to environment and detecting anomalies related to fetal suffering.     

Beam calibration without a phantom for creating a 3-D freehand ultrasound system

To create a freehand three-dimensional (3-D) ultrasound (US) system for image-guided surgical procedures, an US beam calibration process must be performed. The calibration method presented in this work does not use a phantom to define in 3-D space the pixel locations in the beam. Rather, the described method is based on the spatial relationship between an optically tracked pointer and a similarly tracked US transducer. The pointer tip was placed into the US beam, and US images, physical coordinates of the pointer and the transducer location were simultaneously recorded. US image coordinates of the pointer were mapped to the physical points using two different registration methods. Two sensitivity studies were performed to determine the location and number of points needed to calibrate the beam accurately. Results showed that the beam is most efficiently calibrated with approximately 20 points collected from throughout the beam. This method of beam calibration proved to be highly accurate, yielding registration errors of approximately 0.4 mm.